Radioactive waste is transported from various locations throughout the United States to storage locations such as Waste Isolation Plants (WIP). The waste is placed inside of containers, either steel bodies or special boxes, which are in turn sealed inside of special transport devices. A current design of such transport devices is sometimes referred to as TRUPACT-II. Typically, the transport devices are sealed from the ambient environment and are designed to withstand relatively high internal pressures.
While the transport devices are designed for relatively high internal pressures, the waste containers themselves are not. Many gases may be generated by the waste in a container. For example, hydrogen gas may be generated by radiolysis. Therefore, in order to prevent pressure from building-up within the waste container, the container may include one or more vent openings for the equalization of pressure between the interior and the exterior of the container. To prevent the release of particulate matter from the container, conventional containers include a filter assembly positioned across each vent opening and an elastomeric material, such as rubber, is used to seal the filter assembly to the container. The filter assembly is typically a block of porous carbon material which is sealed with an organic cement.
This conventional arrangement has several disadvantages. For example, the carbon block is brittle and, therefore, is not particularly rugged. Also, the carbon block may weaken when it is exposed to moisture and other environmental elements. Consequently, it is subject to cracking and disintegration due to physical shocks, such as jarring, which can occur during transport. Additionally, carbon blocks exhibit limited fire resistance and inconsistent filtration efficiency levels. Further, both the organic cement and the elastomeric seal may deteriorate after extended exposure to the elements inside and outside of the container. Elastomeric materials may also present compatibility problems with respect to the filter assembly and the container materials.